Weight lifting, in addition to being a sport unto itself, is practiced by a significant number of individuals training for a variety of different sports, as well as by those desiring to just generally stay in shape. Thus, people with a broad range of physical conditioning lift weights. Therefore, weights must be readily adjustable in order to be lifted by a variety of people at various levels of skill and conditioning.
Typically, adjustable free weights in the form of barbells are employed with a plurality of weights selectively placed on an associated bar and lifted. The weights are usually circular discs with a hole in the center thereof. A weight is placed on the bar by aligning the hole in the weight with the bar and sliding it onto the bar. Adjustability is provided by adding weights of the desired amount onto the bar.
Opposite end regions on the bar are configured for placing the weights thereon. A stop is provided on the end region of the bar to prevent the weights from sliding onto the central area of the bar that is gripped for lifting. After the desired weights are added onto the bar, a removable collar of some sort is positioned on the bar against the weights to secure them onto the bar as well as to keep them from shifting or otherwise moving as the bar is lifted and lowered.
Many types of collars have been developed to retain weights on a bar. These range from the very complex to the very simple. The more complex collars are generally required for retaining a greater amount of weight on the bar.
Simple collars, having a screw that can be tightened on the bar once the collar is placed snugly against the weights on the bar, are known in the art. These screw type collars are difficult to tighten by hand and have a tendency to dent or otherwise damage or deform the bar.
More complex collars typically include a coil spring-like resilient portion which can be expanded by pressing two handles together. The resilient portion, when expanded, slips over the bar and can be placed snugly against the weights. Once the handles are released, the resilient portion contracts around the bar, thereby gripping it. However, when a great amount of weight is desired to be retained on the bar, these resilient collars exert insufficient force to keep the weight in place.
Other collars which use a resilient member to clamp or otherwise lock a collar onto a bar are limited in their gripping strength, and do not adequately prevent heavy weights from moving or slipping on the bar. A flexible collar in which a downward force is applied to expand the collar while slipping it on the bar also has limited gripping strength.
A collar which requires deforming a portion of the collar to secure the collar onto the bar while urging the collar against the weights to be secured onto the bar requires precision in placing it on the bar. If this collar is placed too close to the weights, there is insufficient room for the collar to advance along the bar. If the collar is initially placed too far from the weights which it is to secure on the bar, the weights are not snugly retained on the bar and can spin, wobble or slide. Since balance is a critical aspect of lifting weights, weights that spin or wobble on the bar can detract from stability and control during lifting.